Best available cop



BEST AVAILABLE COP.

Nov. 11 1924. 1,514,840

I F. G. ERNST METHOD OF MANUFACTURING PIANOS Filed Dec. 17. 1920 8Sheets-Sheet l BEST AVAiLABLE COP.

Nov; 11 1924. 1,514,840 z I F. G. ERNST METHOD OF MANUFACTURING PIANOS IFiled Dec. 1'7. 1920 8 Sheets-Sheet 2 @W a @9 I I l I l I 5 I i i l I ig i i ll I V7 i I l 1 l l l i i L i I i i i .1 1 I I I 9 1 T Il" {I'm-37 40 V t fir? %+& m. /o'

L 13 I ---------8.---- I \Vl/ L 75 40 b BEST AVAILABLE COP.

F.G.ERNST METHOD OF MANUFACTURING PIANOS Nov. 11 1924. 7 1,514,840

Filed Dec. 17. 1920 8 Sheets-Sheet 3 I k awpent op Lfi w m FM; 81m; M

BEST AVAILABLE oo r F. G. ERNST METHOD OF MANUFACTURING PIANOS Nov. 111924. 1,514,840

Filed Dec. 17, 1920 8 Sheets-Sheet 4 wig/0,

BEST AVAILABLE COP.

Nov. 1'1 1924.

F. G. ERNST METHOD OF MANUFACTURING PIANOS 8 Sheets-Sheet 5 Filed Dec.17 1920 awwemtoz 3515b G am W13 BEST AVAILABLE cop.

Nov. 11 1924. 1,514,840

F. G. ERNST I METHOD OF MANUFACTURING PIANOS I Filed Dec. 17. 1920 8Sheets-Sheet 6 m A A a &

3513 '44 flame/11s PAM-AMM- M BEST AVAILABLE cor.

F. G. ERNST METHOD OF MANUFACTURING PIANOS Nov. 11 1924.

Filed Dec. 17 1920 8 Sheets-Sheet '7 awuewtoz Z1;

%4 q 35x 4 6mm BEST AVAILABLE COP;

Patented Nov. 11, 1924.

FRANK G. ERNST, OF NE'W Y OBK,

N. Y., ASSIGNOR T DEAN s. EDMONDS, on NEW YORK, N. Y.

; I mn'rnon or ivinnuraorunme PIANOS.

. Applieation filedDeceinber17,1920. Serial No. 431,349.

T 0 all 2072 am it m concern Be itknown that I; FRANK G. ERNST, acitizen of the United States, residing at New York city, in the countyof New York,

State ofNew York,'have inventedcertain new and useful Improvements inMethods of Manufacturing Pianos; and I do hereby declare the followingto be a full, clear, and exact description of the invention, such aswill enable others skilled in the art to which itappertains to make andusethe same.

g y This invention, "relates .to improvements intheiart ofmanufacturing-pianos and in- Althoughlthe modern volvesf'a substantialdeparture from the universalpracticein that: art. y V v piano wasbroughtto a high state'of musicalperfection" many years ago through .a'series-of succeeding inventions and; improvements {in the structure Iand mechanism, no cerrespcndin aavance emanation] used. 'In spite 'ofthelarge scale production whiclil has characterized thisfindustry, themethodv universally employe'd is that off the craftsman, each piano]being individually constructed without re; gard to exact dimensions 'orinterchangedes the building "of a heavy. back or frame (of wood, whichis roughlydimensioned,withkthe ends approximately 'parallel; andperpendicular to the top. 7 Nov attempt is made toward'exactness inshape or size. A' wrest plank or pin block is secured to the frame nearthe upper edge, the sounding board, with the wooden bridges thereon, isapplied beneath the wrest plank. and the metal string plate is fastenedover thesounding board with- .out exact determination of its position onthe frame. .The string hearings on the wooden bridges areset and thebridges are pinned and notched. The tuning pins are thendriven, thepiano is strung and the strings are spaced, and chipped or given thefirst tuning. strings bear no exact relation to the lateral edges of theframe, nor is their angular relation fixed with reference to the edge ofthe wrest plank, which is assumed to indicate the striking line of thehammers, or to;

the wooden bridges.

The lateral edges of the frame are-then planed and grooved by means ofhand-oper I ng pianos as.

sides of the piano, the act1on never fits ac curately. The dampers andhammers must,

As will, be understood, the

- the key-bed, bottom frame, toe rail and bottom board are separatelycutby the case builderto the required length and moujnted, a tediousoperation requiring alarge amount of manual labor character. n The pianois then readytoreceiv'e the action. The ball bolts, to support theaction brackets, are setwith the aid of axte'mplate gauged from thefront of the key bed, and

v has been heretofore, made'in'the method'of the action bracketsarefastened to the frame by means of the top bracket bolts. The position ofthe bracketsineach piano will differ, depending upon the position oftheplate on the frame. The action, which is separately assembled, ismountedon the brackets, but, owing to the lack of any exactdimensioningof the frame or definiterelation of the strings tothe'striking line or therefore, be carefully adjusted to register withthe proper strings. This requires bending of the individual damper stemsand hammer shanks with consequentdistortion. Atfib'est, the" hammersonly] approximate the true striking line of the strings. The keys arenow laid on the key bed to determine their position, and, since .nodefinte relation between the front of the key bed and the abstracts ofthe piano action has been maintained, the keys must be marked fordrilling to receive the capstan screws. The keys are then removed, anddrilled and are replaced in the bed. v The piano is then sent'to the flyfinishing department to receive the key blocks, name rail, shelf, topframe, top and key rail. These are all cutoversize in the case plant andeach must be cutand fitted to the individual piano. The exterior ofithecase is finished by rubbing and polishing, and after tone regulating andfinal tuning, the piano is ready for shipment,

As a result of the method of construc- BEST AVAILABLE COR t-loii outhhedabofi e, themosl; carefully made pianos iave been individual in tone andother qualities because of the unavoidable t a r i'ations in structurewhich were intro- It has always duced during manufacture. beennecessary, therefore, to select a piano known makes being musicallyinferior and liable to rap1d deterioration in tone.

nother disadvantageous result of the hiiitofore pursued in'cdnstructi'ng il 'te ota. PI?! wa ei fi d i s usual mpdssifle to ei ectsubstantial 'rep p eeery where mechanics, skilled in construction, areavailable.

.Stil'l ano h'f'r disadvantage of the establi slfe d, n'ithda is the. fd ifliculty of detecting ,ea ls'sworkmanshi No standard being'tlieworlrinan proceeds i vith'out check .to ntrodueesu'ch yar a'tiohsas suit his con- 3; e 1en e'xp' ting 'tho'se who follow him to tjoregifsteiiiwitl'i the strings. That 7a.. .1 ,4 o Vercome any efects ofconstruction whic 'he may'i'iitroduc'e. lflewertheless, 111th.ufacturers have always 'cl' "gfo the t at fpi'an'os could not bewisefniaiiufadtu red than by a method i'nvol'yin'g cutting- 10f caseparts to, V fit .aaaaa foughiysra a back 'orframe, and the in z'itable,bending and twisting of the ,actidn paits' to enable the hammers ,and

su'ci a method-is unecionoinical because of {thetiirie, rjeirlli'liredfoi niainifacture and also Iea;ds,'t',0 infeifigr ali tyfo f thenstrument, is

apparent. No better method was (flown heretofore, and, since allina'mifacfins-Brewers confronted with the samelaclr 6f uniformity cftheir, product, they have been easiest to sell -theipin ferior pianos tothose discrin'iinating musical taste, depending upon the occasionallyfine instrumentsproduced-to maintain their reputation with the morecritical public.

. y The objectlof ithe present. invention is to a. method of,manufacturing pianos whereby the; production of instnuments of 'ir'ier'e,u a rdrai quality is attained and the fiiia'h'ufacti iringojer'atio'nsare considerab y expeditedfa method, moreover, which obyia'tes the, necessityof adjusting the parts of the action to 'eachindividual piano and which redi'ic es materially the labor andmaterial-cost of constructing pia'nos, while in- ,suringthe; immediatedetection of careless 'wei-imm'ris' I 1 A further object of theinvention is the Iprovi'sihn. of a -.method of manufacturing pianoswherein all parts are interchangeable and [replaceable from stock, thusmaking it bssible to fsatisfactorily repair a piano which lias beendamaged, without returning theinstrument tothefact ory, v

Contrary to the generallyhcc epted idea "the upper edge of thesuccessfully standardized and constructed to definite and predetermineddimensions, and,

with extreme care, manypianos er the best fact, that pianos thusconstructed are uniformly superior in workmanship and quality; Theadvantages of the novel method are indeed numerous and cumulatiye to thepurcha'se'r'as well as the manufacturer. The latter is enabled toproduce aged insti'i'iifnents. Inasmuch as all of the abetter piano at alower cost, while the fornier is assured that the piano, with reasonablefcare, will maintain 1ts muslcal Iqiiality, ginegms of the causes of thedeterioration heretofore experienced are eliminated'b'y the employmentof the 'n'ew method. in constructing a piano in accordance wi'th the newmethod, the usual form of lreayy frame or back built ofhoriiontalandupri hi ir'fernbe'rs care being taken that 'the'uppe 'edgeisstraight, To the face of I raine. The lower edge of the .pin block isthen finished by means ef a powerdriven milling machine or othersuitable ddyice o er "a or template,

it is parallel to and at a predetermined distance from the upperedge ofthe frame. The line thus fixed, indicates the hammer striking line,which is "about one eighth an inch below.

The sounding board is prepared with a straight- 'upper edge and with theright hand edge perpendicular thereto. The left hand edge and the bottomedge are oversiz'ed about one fourth inch to allow for bellying. Thesounding board is disposed in a gluing press provided witha templatewhich determines the positions of the ribs on the back of the board withrespect tothe upper and righthand edges thereof. The ribs are glued inthe press and the board is removed to another press, which similarlydetermines the positions of the bass and treble wooden bridges which areglued to the face of the board, also in exact relation to the upper andright hand edges thereof with a jig or template. hen the board. iscomplete, it is secured to the lining on the frame with its upper edgeabutting the lower edge of the pin block and its right edge flush withthat of the frame Throughout the construction of the back and soundingboard, exact dimensions are followed.

The cast metalstringfplate isprovided with a rib at itsback, and thisrib is machined to 'a straight edge at a predetermined distance from thetop iron-base bridge on the faceof the plate at the last bass note onthe left hand side, and the iron bridge at the last treble note on theright ha'n'd side.

BEST AVAILABLE COP.

The plate is then laid upon the sounding board, with the machined edgeabutting the lower edge of the pin block. A template is employed to fixthe distance of the middle pin hole for the last treble note from theright hand side of the frame,-so that the bridges on the plate occupya-definiterelation to the striking line of the hammers and the woodenbridges on the sounding board. The plate is temporarily fastened to theframe, and the string hearings on the wooden bridges are determined witha gauge saw. The

plate is then removed and the Wooden I -bridges-areplaned to the stringbearing height which-is determined by. the gauge saw. The bridge pins"are driven at points indicated by a' template'whichis-adjusted i fjthemfas'teried to the frame in the position erpendi'ciilar to the upperedge, and, un

. JII

d er the ordinary method of construction, the

deviatioirof thelateral edges from-the perpendicnlar results in thevariation of the space between the sides of the piano.Moreover,thwidth*of the frames as heretofore congtructed differs in'eac'h'piano. These conditions'i"eqii ire special fitting of theremainingparts. ofthe piano. To prevent variations ofjthischaracter, theframe, after the strings areappliei'is mounted in a planer,

,this string hereinafter'briefiy described, and provided with a gauge tofix the position of the frame thereon." The gauge preferablyconsists ofa dummy hammer, which is adapted to register with the middle string ofthe last. note in the 'treble scale on the hammer line which is' on'eeighth inch below the iron bridge on When the hammer registers, the

frame is c amped with its upper edge against a straight edge provided'onthe planer bed.

Power is applied to the planer,- which is providedjvith rotating knives.As the bed advances, the lateral edges of the frame and sounding boardare planed parallel to gauge measurements and to a predetermined measurement. between the right hand side and the last treble note on thehammer line. and brought to exact perpendicularity with respect to theupper edge or top of the flziil'lO. Upon its return, the bed travelstwice as rapidly as during the advance, and the edges are automaticallygrooved by the rotating knives, being thus provided with grooves whichfurnish a good gluing surface, because the knives'rotate in the samedirection as that of the return travel of the planer bed.

The frame is removed from the planer and delivered to the side gluer whoapplies the sides of the case, which have been previously finished todimensions in the case plant. Since the width of the frame is fixedabsolutely by the planer, and the lateral edges are exactly parallel andperpendicular to the upper edge, the distance between the sides at everypoint is predetermined and is exactly the same at the top and bottom.This greatlyfacilitates subsequent operations, since the key bottom,bottom frame, toe rail and pedal trap action may be introduced andfastened in place without fitting of any kind. The key bottom isinserted below the cheeks of the piano. A template fits between thecheeks above the key bottom to fix the distance between the cheeks towhich the key bottom is fastened. The key bottom is also secured tobrackets on the string plate.

The piano is next provided with ball bolts to support the actionbrackets, and, in positioning the bolts, :1 template is used whichgauges the distance of the bolts from the front edge of the key bottomand from the right-hand side of the piano. The bolts are screwed intothe key bottom and are gauged with a height gauge to project therefrom apredetermined distance. The top bolts are set with reference to the ballbolts, using a template, made of action brackets, which are milled andbored to predetermined measurements and connected by dummy rails. Thetop bolts are set with their heads at a predetermined distance from thestring plate to the top of the action brackets. The action brackets are.then mounted on the ball bolts and are secured to the frame by the topbolts, the positions of which are accurately determined from the face ofthe plate and the right hand side of the case. Thus, the brackets arepositioned to support the action in predetermined relation to thestrings, which occupy a definite relation to the sides of the piano andthe bridges on the sounding board.

The action and its various parts may be manufactured in the samefactory, although customarily, the action is received complete by thepiano manufacturer with the exception of the hammers and dampers. Theassembled action is mounted in a dummy piano for convenience in mountingthe hammers and dampers, which are fastened in place,

the hammer shanks and damper stems being of predetermined length topermit the hammers to engage the strings at the proper striking line.The action. when con'iplete, is removed from the dummy. and held inreadiness for mounting in any piano which is um der construction.

When the case has been completed to the point previously indicated, thefinished action is mounted in the brackets. The required number of keysis assembled, and,

llli

BEST AVAILABLE c keys require no marking for the capstan ITO screws. Thekeys are therefore drilled previously and provided with capstan screws,which are inserted at a fixed distance from the front ends before thekeys are assembled -on the key bed. The capstan screws register with theabstracts in the action without individual application of the screws ashas been necessary heretofore. Consequently, the drilling and insertionof the screws may be accomplished with automatic machinery, insuringaccuracy and lower cost. It is to be particularly noted that no bendingof the hammer shanks or damper stems is necessary when the action isadjusted, since these members are in exact alignment with the stringsand are adapted to strike on the true striking line of the piano,because the relation of all of these parts has been predetermined andmaintained throughout the construction. Thus, a tedious and costlyoperation of piano construction is entirely eliminated.

The :piano is now substantially.complete and is sent to the finishingdepartment where the key blocks, name rail, shelf, top frame, topand keyrail and all hinges are mounted. All these case parts areiinished tosnap gauge measurements in the case plant-and as delivered tothe-assemblers,- require no fitting of any sort. The ends of all piecesmay be varnished in the case .plant, thus further decreasing the work ofthe finisher. After the parts are mounted, the piano is tone-regulatedand tuned {and the case is rubbed with pumice-and polished 'withrottenstone andwater to bring out the high polish, The caseds'then. oiled offand any pin holesdn the coating-are burnt in withhardshellac.. v Thepiano is then subjected to final tuning'and is ready for ship ment.

In order that the invention may be more readily understood, a piano inits several stagesof construction-has been illustrated inthe'a'ccompanying drawing, but it should be --understood that theinvention is not limited -to any-particular style-or type of piano, andthat the invention is therefore broadly claimed as applied generally tothe constructionof pianos. In the drawing:

Fig; 1 is a vertical transverse section through a piano constructed inaccordance with the invention.

Fig. 2 isan-elevation of the piano frame or -back.

Fig.3 is asection on the line 3-3 of Fig 2.

Fig. 1 is a view in section, illustrating the piano back with thegaugeand milling machine employed in finishing the lower edge of thewrest plank or pin'block.

Fig. 5 is a detail in perspective of the gauge for guiding the millingmachine.

gauge employed Fig. 6 is a plan view 'of the face of the sounding board.v

Fig. 7 is a section on the line 7-7 of Fig. 6.

Fig. 8 represents the template. employed in fixing the bridges on thesounding board.

Fig. 9 is a section on the line 9-9 of Fig. 8.

Fig. 10 is an elevation illustrating the sounding board assembled withthe frame or back.

Fig. 11 is a section on the line 11-11 of Fig. 10.

Fig. 12 is a detail illustrating the method of fixing the position 'ofthe metal ,plate on the frame or back of the piano.

Fig. 13 is a section on the line 1313 of Fig. 1.2

Fig. 15 is a detail in perspective oi the gauge employed in fixing theposition of -the metal .plate. 1

Fig. 16 isa plan view of themetaliplate assembled with the back oriraiiie and sounding board of the piano. I

Fig. 17 is a plan wiew 0f -a .tem' late .for fixing the positionof the.pins?0f. e wood- *en bridges. Fig.18 'is a section on theiline 18-118of Fig. 19 is an elevation, partially, ,seotion, of I ishing the frameor .back' ohthe, piano...

Fig. 20 is a front elevation qi the-jnaehine.

Fig. 21 is a detail .in elevationindioating the gauge on the planingmachine,-

Fig. 22 is-a detail in nelevgitiondo} the plate, indicating the methodbistringing the piano.

Fig. 23 'is a detail in perspeetive of a in-ispacingthestrings.

Fig- 24 is a diagrammatical illustration of a .piano case indicating themanner in which *the sides are a pIied tQtheQframe a is a section on theline l 1-14 of 'or back.

Fig. 25 is a view in perspeetive ofithe gauge employed in :-fixing the,relation of thesides at the=cheeks.

Fig. 26 is a detail: in section, illustrating the assembly of the keybottomand keys in the piano. I The detailed operations of constructingand assembling-a. piano in accordance with the present inventioninvolve,-as stated here tofore, the continued-application ofgauges orother devices adapted. -to.,insure. exact n'ieasuremen'ts, andparticularly a.;predetermined relation between the stmngs.- and bridgesandthe sides of-thepianm andipare ticularly the relation-of-the supportsfor the action to the strings, in order-thatthe-hammers may strikefairlyf at predetermined points on tho-strings. In constructing a aplaning machine employedan fin- BEST AVAILABLE COP.

piano, therefore, a frame is built, consisting of upright posts 5,rabbeted at the top and bottom to receive horizontal top members 6 and 6and bottom members 7, respectively, with intermediate blocks 7 betweenthe posts; the frame being of rigid construction, securely fastened toprovide the necessary strength. Supports 10 for the sounding board aresecured to the frame. The upper edge 8 of the frame is finished to astraight line and the two ends are approximately perpendicular thereto.A wrest plank or pin block 9, which is built up of suitable veneer, issecured to the frame with its upper edge flush with the edge 8. Theframe is then mounted on a table 10, and an angular gauge 11 is arrangedthereon and secured by a clamp 12 to indicate the desired position ofthe lower edge of the wrest plank, which must be exactly parallel withthe upper edge thereof and of the frame. The gauge is provided with aslot, having an edge 13, which serves as a guide for a roller 1% on theshaft of a milling machine, preferably driven by an electric motor 15. Amilling cutter 16 is arranged on the shaft below the roller, and, whenthe milling machine is moved along the gauge with the roller in contactwith the edge 13, the rotating milling cutter finishes the edge of thewrest plank-in exact parallelism with the upper edgeof the frame and ata predetermined distance, a, therefrom. i

Meanwhile, a sounding boa-rd, 17, is prepared and supported in asuitable template similar to that hereinafter described in connectionwith the fixing of the bridges. The upper edge of, the sounding board isfirst finished with a straight line and the board isthen fixed in thetemplate with its upper and right-hand edges engaging suitable gaugesthereon. The template fixes the place of the ribs 18 on the back of thesounding board, which are glued thereto under suitable pressure. lvl enthe glue has hardened, the sounding board is removed, and the ends ofthe ribs 18,- adjaeent the edges thereof, are cut away fro-facilitateassembling of the sounding board with the frame of the piano. Beforemounting the sounding board on the frame, it is supported in a template19 with its upper and righthand edges engaging suitable gauges thereon.Gauges 20 are then brought down upon the face of the sounding board tofix the position of the treble and bass wooden bridges 21 and 22, whichare glued to the face of the sounding board under suitable pressure. Thesounding board, when the glue is dry, is assembled with the frame bybringing the upper edge into engagement with the shoulder 23 of thewrest plank, which was formed as indicated, by the milling machine andby adjusting the right-hand edge of the sounding board, until it coincidcs with the right-hand edge of the frame.

Thus, the wooden bridges on the sounding place by screws 24, whichengage the upright members 5 of the frame.

A metalplate 25 is provided with a rib 26 at its rear face, the upperedge of which is machined accurately to a straight line a predetermineddistance from the iron bridges on the face of the plate, and the plateis next assembled with the frame, by laying it upon the sounding boardwith the straight edge of the rib 26 in engagement with the shoulder 23of the wrest plank. The lateral position of the plate with reference tothe edge of the frame is fixed by a gauge 27, having a depending arm 28adapted to cooperate with the edge of the frame, and a pin 29, which isadapted to enter the hole provided for the middle pin for the lasttreble strings Thus, the position of the treble and bass bridges 30 and31 on the metal plate are fixed relatively to the upper and right-handedges of the frame, and,

consequently, bear a' predetermined relation to the wooden bridges onthe sounding board. The string bearing on the wooden.

bridges is next determined by the saw gauge, and the metal frame is thenremoved. The wooden bridges are planed tothe string bearing height asdetermined by the saw gauge andpainted with black lead formark ing. Atemplate 32, having a; plurality of openings 33, is employed on thewooden bridge.

ion

in fixing the pins 1 The template 32' rests with its upper edgeagainstthe shoulv der 23:01 the wrest plank and is provided with 'a'depending lug 32" adapted abut the right-hand edgeof the frame.

When the pins have been inserted in the wooden bridge, 21, the metalplate is mounted on and fastened by suitable boltsto the piano frame,and the piano is strung in the manner indicated in Fig. 22. When thestringing is complete, a guage 34 is employed to determine the relativepositions ofthe middle string of each set on the metal bridges 30, and achipping tool 35, having I triple slots 36, is employed to fit therelative positions of the strings of each set, the operation beingtermed chipping, and 1n.-.

cluding the preliminary tuning of the instrument. The frame and plateare thus complete except for the fact that the ends of the frame are notexactly perpendicular to the top; it being practically impossible tosecure parallelism of these edges by the use of ordinary hand tools.Since it is a fundamental requirement to the successful manuv facture ofpianosin accordance with the invention' that the sides of the frame beexactly perpendicular to the upper edge and, parallel to each other,means are provided to BEST AVAILABLE COP.

insure-this result. The means include a special planing machine adaptedto receive the franie'a-fter the plate. and strings have been appliedthereto, and toplane the edges of the frame without disturbing theposition of the bridges and "strings with respect to theseedges.

The machine is illustrated in Figs. 19-21 of the drawings and, briefly,comprises a rigid support 37, carrying a movable-bed 38, which isadapted to be advanced through the operationof certain mechanismprovided for this' pur oseand driven from a source of power. guch'mechanism is common to planing machinesandneed not be described indetail therefore,- herein. Upon I the. bed 38,

a straight edge 39 is provided, which prefer ably carries adjustablepoints 4:0, adapted to grip the piano I frame when its upper edge isdisposed against the straight edge 39. On thepppositeendof the;bed, anadjustable clamp this adapted to engage the bottom, edge' 'ofthe frameand to hold the frame se-,

purely onthe bed; Rota-table cutters 42 are supperted, on shafts43at theopposite sides of the support 37 and are adaptedto be rotated throughsuitable connections, referably helts 4c4 engaging pulleys4=5 and withdriving pulleys actuating from a suitablesource of power.

Inadjusting he i position: of, the piano frame upon the bed 88, it isnecessary to insure that the relation of the stringsto the sides of theframe is not destroyed in planing. .;Consequently, a gauge 45 is adjustably'imounted on a depending support e6, which is in turn adjustable ona cross-bar 417, so that the planingmaohine may be adapted to theproduction of pianos of different sizes. The gauge preferably has theform of a hammer 4.8, which, when lowered, is intended to engage themiddle string of the set which sounds the last treble note of thescale,' as 'indicatedin Fig. 21. lVhen the gauge is properly set, theframe resting on the bed isshifted laterally until the ham-- merproperly cooperates with the string indicated; whereupon the frame isclamped on the bed and the hammer is lifted.

Power is then applied to advance the bed 38 and rotate the-cutters 42,which plane the lateral edges of the frame to exact parallelism andperpendicularity to the upper edge. The bed advances at a uniform rateuntil ;the edges have passed the cutters and thengreturns at anincreased speed, preferably double thatofits advance. As it travels thusthe same direction as that of rotation ofthe cutters, the edges aregrooved or provided. with shallow corrugations which furnish 'asplendidgluing surface and insure rigid fastening of the sides of thepiano to the frame.

.The frame nowtransferred to the sidegluer, who applies the sides 49 t9the ends planin machine.

' inserted of the frame. The sides are previously con- The sides arevarnished before they are delivered for assembly with the frame, Inapplying the sides to the frame, a gauge 50 is employed, -against whichthe sides are clamped so that/the distance 0, (Fig. 24) is' exactly thepredetermined length of the key bottom 51, and also of such a lengththat the sides'squarely fit the frame as finished in the 1 and securedin place together with a bottom frame 52', the toe rail and pedal trap"action, and the piano is ready to receive the actioni r The action,indicated generallylin Fig. 1 at 56,. is preferablyfitted in a dummypiano,

as previously described, hammers andjdampeis, and is ready for, mountlngin the The key bottom 51 is next piano sup-port the action: ball 57 Iare driven "in-the 'key ibotto'm 51 at a pre'-..

determined distance from the front edge thefgeofahd in fiiredfrelationto 'the sides" of h P -111 la e han mass this purpose; Thus,"theaction"andfevery'v element thereof, when. mounted on the ball. Ibolts, will bear a fixedrelation to'the sides of the piano, which, aspreviously'indicated,

beai 'asi milar relation' to the strings. A

template consist-in g of j action I brackets 58, connected by dummyrails, is supported on the ball bolts 57 and bolts 59 are driven! in thebrackets'are at a predetermined distance from the face of the stringplates ,{lhe brackets and the action 56 are then mounted and secured onthe frame andthe keys 60 are assembled on the key bottom. Since theposition of the action and consequently of thoabstracts 61 ispredetermined, it ,is un-v necessary to specially mark and drill thekeys to receive the capstan screws 62; and the latter are insertedpreferably by automatic machinery in the keys before the latter areassembled. The capstan screws engage the abstracts and are adjustedvertically to frame to the finished piano, numerous operations,heretofore considered essential, are eliminated and others areexpedited, so that the time required tobuild the piano complete ismaterially decreased Furthermore, he instrum when ple ed, i entire yframe of the piano and adjusted until m'achined faces of the railsupports on the' BES free from the common defects of pianos which-resultfrom va-riations introduced during manufacture. Each piano of anyparticular type is identical with every other produced in the same plantfrom the same plans. The elimination ofdistortion of the hammer shanksand damper stems is to be particularly noted,'since this is a fruitfulsource of trouble in constructed. g

The discovery that pianos," though constructed largely of wood, may beaccurate'-' ly fashioned "to exact dimensions and assembled from partspreviously cut and "finished to fit without further cutting by means ofhand tools, is of the highest importance in this art." Theeliminationbfhguid' tools' which have vbeen the cause, heretofore, ofmuch inferiority in pianos, is, in fact,on"e' of the primary'featuresb'f the invention.

' pianos as heretofore- AILABLE COP.

thereon in predetermined and exact relation fWith each other and withthe upper edge of the frame, and thereafter planing the lateral edges toexact perpendicularity with the upper "e'dge'fthe planing being gaugedfrom a given string, whereby the relation of the strings and bridges tothe lateral edges is This, with the application of the principl'e'entlywithpredetermineddimensionsadapt of following exact dimensions "andpredetermination'of the relative position of'the parts; and particularlythe position of the bridges" and strings with reference to the loweredge of the pinblock and the side of the piano, insuresthe successfulconstruct-ion ed for assembling with the frame and'assem bling the caseparts on the frame."

" 5.; 'The'im'provementin the art of "manufact'uring' -piano's,which"co'mpri ses assembling the-frame, soundm'gboard and plate of apiano witli' the -bridges and strings of pianos of uni formeuality. Therespee thereon in predetermined and exact relation tive" parts er-pianosconstructed 'inaccord withjeach other'and with the upper edge of ancewith the invention are interchangeable to the"'factory.Careless"workmanship is, of course, immediately"detected-because, ifvariations are introduced, the pia fiol camiot be assembled.Theelimin'ation of most of the ha-nd'work materially aids intheproduction ity.

v i Obviously, various changes may""be made in the details of theseveraloperations within the scope of the I accompanying claims withoutdeparting from the invent-ion or sacrificing any of its advantages. r

I claim: g Y

1. The improvement in the art of'n1anufacturing pianos, which comprisesassembling the frame, sounding board and plate of a piano with thebridges and strings thereon in predetermined and exact relation witheach other and with the striking point of a selected hammer of the pianoaction.

The improvement In the artof manufacturing pianos, which comprisesasseml the frame, and thereafter planing the lateral throughout, andrepairs may consequently edges to exactperpendicularity with the upbereadily made withoutret'urning'thepiano "strings and bridges to thelateral edges is fixed, preparing the case parts independently' withpredetermined dimensions adapt- "ed for assembly withthe frame,assembling sides of the piano and the strings.

'(SJTheimprOVem'ent in the artof manu v 'facturing pianos, whichcomprises constructing frame with the wrest plank thereon, finishing thelower edge of the wrest plank to exact parallelism with the upper edgeof the frame and at a fixed distance therefrom,

and finishing the lateral edges of the frame exactly perpendicular tothe upper edge of the frame, and in exact relation to the striking pointof a selected hammer of the piano action.

7. The improvement in the art of manufacturing pianos, which comprisesconstructing a frame with the wrest plank thereon,

bling the frame, sounding board and plate finishing the lower edge ofthewrestplank of a piano with the bridges and strings thereon inpredetermined *and' exact relation with each other and'with the strikingpoint of a 'seleeted'hammer'of the piano action, and thereafter'planingthe lateral edges to exact perpendicularity with the upper edge.

3. The improvement in the art'of manufacturing pianos, which comprisesassembling the frame, sounding board and plate of a piano with thebrldges and strings to exact parallelism with the upper edge of theframe and at a fixed distance therefrom, applying the sounding'board,string plate and the strings to the frame, and finishing -the lateraledges of the frame and sounding board exactly perpendicular to the upperedge of the frame and in exact relation to the striking point of aselected hammer of the piano action. e 8. The improvement in the art ofmanuof a piano with the'bridges and strings fixed, preparing the caseparts independ of an instrument of "standardqualthe caseipart's on'theframe' and mounting the action in predetermined relation to the BESTAVAILABLE COP.

facturing pianos, which comprises constructing a frame with the wrestplank thereon, finishing the lower edge of the wrest plank to exactparallelism with the upper edge of the frame, and at a fixed distancetherefrom, applying the sounding board, string plate and the strings tothe frame, finishing the lateral edges of the frame and sounding boardexactly perpendicular to the upper edge of the frame and in exactrelation to the striking point of a selected hammer of the piano action,and exactly fixing the supports for the action on the frame withreference to the lateral edges of the frame.

9. The improvement in the art of manufacturing pianos, which comprises,constructing a frame with the wrest plank thereon, finishing the loweredge of the wrest plank to exact parallelism with the upper edge of the.frame and at a fixed distance therefrom,"applying the sounding board,string plate and the strings to the frame, finishing the lateral edgesof the frame, and sounding boardexactly perpendicular to the-upperedgeof the frame and in exact relation to the striking point of a selectedhammer 0f the piano action, exactly fixing the supports for the actionon the frame with reference to thelateral edges thereof and mounting theaction as a unit upon the supports provided-therefor therebybringingfthe SeleQtBd hammer into exact cooperative relationship withits striking point. v i Y 10. The improvement in the artof manufacturingpianos,-;which comprises, constructing a frame with.;the wrest plank toexact parallelism. with theiupper-edge of the frame and at a fixeddistance therefrom, applying the so mdingboard, string, plate and thestrings to thes-framoy finishing the lateral edges exactly perpendicularto the upper edge of the frame and in exact relation to the strikingpoint ofa selected hammer of the piano action, separately assemblingthepiano action in a, dummy frame of standard dimensions and mounting theassembled action as a unit upon the supports provided therefor inpredetermined relation to the lateral edges of the frame.

11. The improvement in the art of manufacturing pianos, which comprises,assembling the action with the hammers and dampers with reference tofixed and predetermined striking points and subsequently mounting theaction 'as a unit in the frame of the piano in predetermined and exactrelation to the lateral edges of the frame.

12. The improvement in the art of manufacturing pianos, which comprises,assembling the action with the hammers and dampers in a dummy frame andthereafter mounting the action as a unit in the frame of the piano inpredetermined and exact relation to the lateral edges of the frame.

13. The improvement in the art of manufacturing pianos, which comprises,con structing the frame of a piano of standard and exact dimensions,independently assembling the action with reference to fixed andpredetermined striking points and subsequently mounting the action as aunit in the frame in predetermined and exact relation to the lateraledges thereof.

14. The improvement in the art of manufacturing pianos, which comprises,constructing a frame of a piano of predetermined and exactdimensions,fixing the supports for the piano action in exact relation to thelateral edges of the frame, separately assembling the action withreference to pre determined striking points, and subsequently mountingthe action as a unit in the frame.

15. The improvement in the art of manufacturing pianos, which comprisesconstructing and stringing a frame, planing the lateral edges to exactperpendicularity to the upper edge and in definite relation to thestriking point of a, selected hammer Of the action, separatelyassembling the action -with reference to predetermined striking points,and subsequently mounting the ac- --tion vas a unit on the frame. 7 v

16. The improvement in the art of manu. facturing pianos, wh chcomprises constructing a frame w th the wrest plank thereon, finishingthe lower edge of the wrest plank to exact parallelism with the upperedgeof the frame, finishing the edge of a rib on the back of the stringplate in exact relation with the bridges thereon, and

mounting the string plate on the frame with the finished edge of theribabuttingthe lower edge of the wrest plank.

l7. The improvement in the art of manufacturing pianos, which comprisesconstructing a frame with the wrest plank thereon, finishing the loweredge of the wrest plank to exact parallelism with the upper edge of theframe, finishing the edge of a rib on the back of the string plate inexact relation with the bridges thereon. mounting the string plate onthe frame with the finished edge of the rib abutting the lower edge ofthe wrest plank, and fixing the'position of the stringplate on the framewith reference to the lateral edges thereof.

-18. The improvement in the art of manufacturing pianos, which comprisesconstructing a frame with the wrest plank thereon, finishing the loweredge of the wrest plank to exact parallelism with the upper edge of theframe, finishing the edge of a rib on the back of the string plate inexact relation with the bridges there, mounting the string plate on theframe with the finished edge BEST AVAILABLE of the rib abutting thelower edge of the wrest plank, fixing the position of the string plateon the frame with reference to the lateral edges thereof, and thereafterplaning the lateral edges of the frame to exact perpendicularity tothe'upper edge thereof.

19. The method of making a piano, which consists in building a frame,planing opposite side edges of the frame simultaneously so that theywill be in exact parallelism and at a predetermined distance apart, andbuilding up the piano by applying sides and other parts to the frame,whereby parts drawn from stock may be employed without special fittingof each part.

20. The method of making a piano, which consists in building a framehaving its lateral edges in exact parallelism and at a predetermineddistance apart, and building up the piano thereon by applying sides andother case parts to the frame, whereby case parts drawn from stocks ofduplicate parts may be employed without special fitting of each art. p21. The method of making a piano, which consists in building a frame,mounting there on a sounding board and plate, shaping the lateral edgesof the frame simultaneously to bring them to exact parallelism with eachat a predetermined distance from a predetermined point on the plate, andbuilding up the piano by applying sides and other case parts, etc.

22. The improvement in the art of manufacturing pianos, which comprisesconstructing a frame with the wrest plank thereon and with the upperedge in exact parallelism with the lower edge of the wrest plank at afixed distance therefrom and finishing the lateral edges of the frameexactly perpendicular to the upper edge of the frame and in exactrelation to the striking point of a selected hammer of a piano action.

23. The improvement in the art of manufacturing pianos, which comprisesconstructing a frame with the wrest plank thereon and with the upperedge in exact parallelism with the lower edge of the wrest plank at afixed distance therefrom, applying the sounding board, string plate andstrings to the frame, and finishing the lateral edges of the frameexactly perpendicular to the upper edge of the frame and in exactrelation to the striking point of a selected hammer of the piano action.

24. The improvement in the art of manufacturing pianos, which comprisesconstructing a frame with the wrest plank thereon and with the upperedge of the frame in exact parallelism with the lower edge of the wrestplank at a fixed distance therefrom, finishing the edge of a rib on theback of the string plate in exact relation with the bridges thereon, andmounting the string plate on the frame with the finished edge of the ribabutting the lower edge of the wrest plank.

In testimony whereof I afiix my signature.

FRANK G. ERNST.

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